1. Field of the Invention
This invention relates generally to improvements in oil field equipment, and more particularly, but not by way of limitation, to improve apparatus for moving lengths of drill pipe or casing back and forth between a drilling rig pipe rack and the floor of a drilling rig.
2. Description of the Prior Art
During the drilling of an oil well it is necessary to move lengths of drill pipe and casing into an upright position in the derrick of the drilling rig from a substantially horizontal position on the pipe rack adjacent to the drilling rig. It is also necessary to remove lengths of drill pipe or the like from the derrick and place them on the pipe rack from time to time. One means of moving such lengths of pipe from the pipe rack is to attach a cable extending downwardly from the upper portion of the derrick to one end of each length of pipe to be moved from the pipe rack to the floor of the drilling rig. The cable is then pulled up into the derrick by suitable winch means to drag the length of pipe along the walk and up a ramp extending from the walk to the floor of the drilling rig through the V-door of the derrick until the length of pipe is positioned vertically within the derrick set in a desired position on the floor of the rig. During the movement of pipe in this manner, the threads on the pipe are often damaged and other damage to the pipe is sustained. Movement of large diameter lengths of casing in this manner is also extremely hazardous to the relatively expensive casing and dangerous to the personnel working on the rig due to the weight of the lengths of casing.
Other means have been used to provide improved movement of the lengths of pipe or casing from the pipe rack to the drilling rig derrick and floor such as by permanently installed hydraulically actuated masts which are mounted directly to the drilling rig. Such masts, however, remain idle a great portion of the time since movement of lengths of pipe and casing between the pipe rack and the rig floor is not a continuous process during the drilling of an oil well.
Another means employed, particularly in the handling of large diameter lengths of casing, involves the use of large, expensive truck-mounted steel erection derricks for lifting and handling lengths of casing. The latter method is relatively expensive due to the costs involved in employing the derrick and the derrick operator.
The present invention contemplates a pipe handling apparatus for moving drill pipe and casing back and forth between a position reclining on the horizontal drilling rig pipe rack and a position on the rig floor via the V-door of the drilling rig. The apparatus includes a support frame, a bifurcated mast having first and second ends and pivotally secured to the first end thereof to the support frame, and clamping means carried by the support frame for securing the support frame to the drilling rig pipe rack whereby the mast may rotate relative to the support frame about a horizontal axis. The apparatus further includes power cylinder means interconnecting the support frame and the bifurcated mast for rotating the mast about the axis of pivotal securement to the support frame. A first power winch is carried by the support frame adjacent the first end of the bifurcated mast and sheave means are mounted on the second end of the bifurcated mast for rollingly supporting a cable passing thereover. A cable is secured at one end thereof to the first power winch and extends over the sheave means with the opposite end of the cable depending from the second end of the bifurcated mast. The apparatus further includes pipe securing means carried on the opposite end of the cable for releasably securing a length of pipe to the cable, and, control system means for controlling the extension and retraction of the power cylinder to swing the second end of the bifurcated mast from a position extending over the rig pipe rack to a position adjacent to the V-door and floor of the drilling rig and, alternatively, from a position adjacent to the V-door and floor of the drilling rig to a position extending over the drilling rig pipe rack, and for controlling the operation of the first power winch to alternately wind and unwind the cable thereon.
An object of the invention is to provide apparatus to increase the efficiency of moving drill pipe and casing back and forth between a position on a drilling rig pipe rack and a position on the drilling rig floor.
Another object of the invention is to provide pipe-handling apparatus for use in moving drill pipe and casing between a drilling pipe rack and the floor of the drilling rig which apparatus is readily transportable between various drilling rigs in an oil field.
A further object of the invention is to provide improved pipe-handling apparatus for moving drill pipe and casing back and forth between the pipe rack and the rig floor which prevents damage to the pipe casing during the movement operation.
A still further object of the invention is to provide a pipe-handling apparatus for moving drill pipe and casing back and forth between a pipe rack and the rig floor which is readily transportable, simple to install and remove from the drilling rig, and economical in construction and operation.
Other objects and advantages of the invention will be evident from the following detailed description when read in conjunction with the accompanying drawings.